Boring into the earth is an important activity in many industries, such as mining, oil and gas drilling, prospecting and tunnel construction. A wide variety of methods and various different types of bits are available for this purpose. There are three contrasting approaches that are commonly used for boring into the earth in the oil and gas drilling, mining and construction industries, namely rotary shear drilling, roller cone drilling and percussion drilling.
The principal types of drill bits used in rotary drilling operations are roller bits and fixed cutter bits. In roller bits, roller cones are secured in sequences on the bit to form cutting teeth to crush and break up rock and earth material by compressive force as the bit is rotated at the bottom of the bore hole. In fixed cutter bits, Polycrystalline diamond compacts (“PDC”) cutting elements on the bit act to cut or shear the earth material. The action of some flushing medium, such as fluid drilling mud or compressed air, is important in all types of drilling operations to cool the cutting elements and to flush or transport cuttings to the upper surface of the well. It is important to remove cuttings to prevent accumulations that will “ball up” or otherwise interfere with the crushing or cutting action of the bit and the cooling action is particularly important in the use of PCD cutters to prevent carbon transformation of the diamond material. In deep well drilling the circulation of drilling mud is contained in the wellbore hole and can be recaptured and controlled at the well surface.
A PDC cutting element typically includes a superabrasive diamond layer, also known as a diamond table. The diamond table is formed and bonded to a substrate using an ultra-high pressure, ultra-high temperature (“HPHT”) process. The substrate is often brazed or otherwise joined to an attachment member, such as a stud or a cylindrical backing. A stud carrying the PDC can be used as a PDC cutting element when mounted to a bit body of a rotary drill bit by press-fitting, brazing, or otherwise securing the stud into a receptacle formed in the bit body. The PDC cutting element can also be brazed directly into a preformed pocket, socket, or other receptacle formed in the bit body. A rotary drill bit typically includes a number of PDC cutting elements affixed to the bit body.
A need exists for a drill bit head that is a variant to revolving cones on roller bits that reduces wear on the drill bit through the use of cutting discs with projections and angles that shear away the material being bored.
The present embodiments meet these needs.
The present embodiments are detailed below with reference to the listed Figures.